According to the Airbnb guest, the cigarette odor permeated every part of the building, including the foyer/common areas and the Airbnb unit.My Airbnb guests left me a scathing 2 star review, with one star for value and cleanliness due to the odor.

LOL, in college my roommate set the apartment on fire by throwing a lit cigarette in a trash can. 

We can assume the smokers are putting the cigarette butts in the drains and the wipes are coming from the parents, but people always want to argue that you can't prove any of that.

The first tenant says their stuff smells like cigarettes all the time as a result (they live above the suspected smokers).The smoker denies they smoke in or around the house, but I’ve seen the cigarettes around the house and have reason to believe the complaint.The lease clearly says no smoking allowed in the house or within 30 ft of the structure.

My landlord even seen the husband walk out of the house with a cigarette in his hand.

They continuously smoke cigarettes in the house when they are here and none of us smoke.

I'll tell you a bit about where my 4-unit is located and what I deal with:-Located across the street from a bar (a neighborhood bar - nothing too rowdy) so there are beer bottles and cigarette butts on my curbside grass fairly regularly-My credit score requirement is 625 for C-class.

The tenants seem like good people but are all heavy smokers (stair case reeks cigarette smell), they are also using the attic for storage (I have no access) and occupying the majority of the side lot for parking.

Allow them to smoke wherever they can smoke cigarettes.

As far as the health affects/ smell/ damage to the property,  it is a different product than cigarette tobacco, and is unlikely to linger or create any damaging issues once the upstairs tenant is removed.